The inventive concept relates generally to semiconductor memories. More particularly, the inventive concept relates to nonvolatile memories having a three-dimensional (3D) structure.
Semiconductor memories are a common feature of most modern electronic devices. They are used for a wide variety of purposes, such as providing long-term data storage, short-term data storage, buffering for ongoing operations, and so on. Different types of semiconductor memories may be used for different purposes based on performance tradeoffs, cost, or other factors. For example, semiconductor memories having faster access times may be used to store more frequently accessed data, while semiconductor memories having greater storage capacity may be used to provide long-term data storage for large amounts of data.
One attribute that can be used to categorize different types of semiconductor memories is whether they are able to retain stored data in the absence of applied power. For example, nonvolatile memory devices retain stored data when disconnected from power while volatile memories lose stored data when disconnected from power. In recent years, there has been a continuing increase in the demand for nonvolatile memory devices based on trends such as the proliferation of mobile devices and an increasing demand for personal data storage. In an effort to meet this ever increasing demand, researchers have continually sought ways to develop nonvolatile memory devices with increased storage capacity and performance.
One approach to increasing the storage capacity and performance of nonvolatile memory devices is to form memory cells in a 3D structure. This is typically accomplished by forming arrays of cells on top of each other in a stacked configuration. The design and implementation of nonvolatile memory devices with a 3D structure raises many technical challenges that can affect performance, reliability, durability, and so on. Accordingly, there is a general need for new techniques and technologies to improve these and other aspects of nonvolatile memory devices having a 3D structure.